Mechanical Degradation and Fracture Behavior of PBF-LB/M Ti-6Al-4V Induced by Rubber-Glove Contamination

This study quantifies the mechanical degradation caused by locally introduced rubber-glove contamination in stress-relieved PBF-LB/M Ti-6Al-4V. Rubber-glove fragments were inserted into defined build layers of standardized tensile specimens and into highly loaded transition regions of a topology-optimized bracket demonstrator. Twelve uncontaminated and twelve contaminated tensile specimens and nine brackets per condition were evaluated. The contaminated tensile specimens exhibited a mean ultimate strength of approx. 860 MPa compared with approx. 1200 MPa for the reference condition, corresponding to a reduction of approx. 28%. Mean elongation at break decreased from approx. 13.4% to 0.6%, representing a reduction of approx. 95%. Fracture preferentially occurred at the contamination insertion region and was associated with planar fracture features and retained spherical powder particles. The results support a predominantly defect-controlled degradation mechanism associated with locally disturbed consolidation.